Windows based network configuration and control method for a digital control system

Abstract

A system for configuring a process control system, e.g., a Fieldbus network, having intelligent field mounted devices coupled to a data communications bus. A software representation of the process control system to be configured is first designed on a computer. Using the system, a user selects representations of the various field mounted devices to be included in the actual control system. The user then specifies which function blocks of each field mounted device are to be used and how those function blocks are to be linked. The computer is then coupled to the communications bus of the actual control system via an interface device and the configuration and link data are downloaded to the field mounted devices of the control system. The computer can act as a bus master of the communications bus of the control system with the field mounted devices acting as slaves. The computer can also be disconnected from the control system communications bus and the control system will operate with one of the field mounted devices acting as the bus master.

What is claimed is: 
     
       1. A method of controlling a passing procedure of a token in a Fieldbus network, the Fieldbus network including a control computer and a plurality of field mounted devices coupled together by a Fieldbus, the token representing an authorization to initiate a bus transaction, the method comprising the steps of: segmenting a passing schedule of the token into at least two segments;   storing a first schedule segment of the at least two segments in a first device of the field mounted devices;   storing a second schedule segment of the at least two segments in a second device of the field mounted devices;   operating the first field mounted device to: I) monitor for an indication of a control computer failure;   ii) when the control computer failure is detected, controlling the passing procedure of the token according to the first schedule segment.     
     
     
       2. The method according to claim 1, further comprising the step of: when the control computer failure is detected and when the token is received from the first field mounted device, operating the second field mounted device to control the passing procedure of the token according to the second schedule segment.